The present invention relates generally to light sources, and more particularly to a system for controlling a plurality of light emitting diodes to produce different light beam patterns.
Control of lighting is needed in many applications, and in particular, precise control of a light source may be desirable. For example, when multiple light sources are used to project light to different locations in close proximity to each other, precise light control is very important. One such application where precise control is very important is in mobile passenger cabins (e.g., aircraft, car or bus). In particular, light sources for these cabins are designed in an attempt to reduce the amount of stray light (i.e., light outside the illuminated area) emitted. This stray light is undesirable for many reasons, including for example, bothering other passengers within the cabin.
In general, including in many mobile passenger cabins, incandescent lights (e.g., reading lights) are used to provide lighting. These lights typically provide adequate illumination for reading (i.e., light provided to a general area), but are difficult to control. Specifically, control of light output shape, intensity or aiming is difficult. There is a compromise between light beam pattern size and shape, and a single illumination pattern is typically provided to meet all lighting situations for a particular application. In situations where a single illumination pattern is not acceptable, mechanical apertures are used to adjust pattern size and shapes, which may be variable or fixed. However, these mechanical components not only add complexity to design, but are often difficult and cumbersome to operate by a user. Further, aiming of a light beam also can be adjusted mechanically, which generally may be provided using a gimble type mount. However, again, the mount is awkward to adjust and requires the user to physically touch the light to adjust the aiming.
High Brightness light emitting diodes (LEDs) are now available that provide sufficient light intensity and full color output spectrum to allow for use in applications where incandescent lamps traditionally were the only option. The use of LEDs allows for the incorporation of additional features into light sources (i.e., fixtures), which are currently not possible using conventional incandescent lamps.
Thus, there exists a need to provide a system for electronically controlling LEDs to provide different light beam patterns from a light source, including for example, variable pattern size and shape, variable aiming and variable intensity of the illuminated pattern. It is also desirable for such a system to provide for selectable control by the user, which preferably may be programmable, depending upon the particular application and environment.
The present invention provides an LED light source that allows for increased control of a projected light beam, including light beam focusing and aiming. In general, the present invention provides for controlling white light and imaging onto a focal plane to produce a predetermined light pattern, which may be used, for example, as a reading light. The invention also reduces or eliminates glare or visible light outside the intended illumination area. The use of LEDs also provides for significant improvement in service life.
The LED light source of the present invention provides for increased control of a light beam, and in particular, the light beam pattern using an array of LEDs. With respect to controlling the light beam pattern, this may include, for example, adjustment of the light beam size, shape, intensity and aiming.
Specifically, an improved light source providing increased control of lighting constructed according to the principles of the present invention includes a plurality of light emitting diodes configured in an array and adapted to be selectively powered to provide different light beam patterns, which may include, for example, different shapes, sizes, and intensities, as well as control of light beam direction. The improved light source may include a color conversion component having a phosphor impregnated material adapted for energization by the light emitting diodes. Further, a collector lens for capturing light from the color conversion component and an objective lens for focusing the different light beam patterns may be provided. An aperture may be used to reduce or eliminate visible glare from the light source when viewed from outside the illumination area.
A programmable controller may be provided for controlling the different light beam patterns. This controller is adapted to provide different current levels to power the array of light emitting diodes and controls switches to activate different light emitting diodes within the array.
The present invention also provides, in combination with a mobile passenger cabin, a plurality of light sources providing illumination within the mobile passenger cabin. Each of the plurality of light sources includes a plurality of light emitting diodes configured in an array and adapted to be selectively powered to provide different projected light beam patterns. A control program may be provided that is adapted to control the plurality of light emitting diodes to provide the different projected light beam patterns. In particular, the control program may control, for example, the size, shape, intensity or projected direction of the light beam pattern. The control program is also adapted to control the current levels to power the plurality of light emitting diodes and to control switches to activate some of the plurality of light emitting diodes.
A method of controlling lighting using a plurality of light emitting diodes arranged in an array is also provided. The method includes selectively powering at least some of the plurality of light emitting diodes to control the pattern of a light beam produced by the plurality of light emitting diodes. Further, a phosphor impregnated member may be used to emit a wide spectrum white light when energized by the plurality of light emitting diodes. The light beam pattern may be shielded from direct view using an aperture.
Thus, the present invention provides an improved light source allowing for increased control of a projected light beam by selectively powering some of a plurality of LEDs arranged in an array. The light beam pattern is thereby controlled, which may include, adjustment of shape, size, intensity and direction of the light beam pattern, among others.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.